The influence of flexible walls on the self-diffusion of CH4 in an isolated single walled carbon nanotube, as an example, was studied by molecular dynamics simulations. By simulating the carbon nanotube as a flexible framework it was demonstrated that the flexibility has a crucial influence on self-diffusion at low loadings. It was shown how this influence could be incorporated in a simulation of a rigid nanotube by using a Lowe-Andersen thermostat which works on interface-fluid collisions. The reproduction of the results of a flexible carbon nanotube by a rigid nanotube simulation was excellent.

Understanding the Loading Dependence of Self-Diffusion in Carbon Nanotubes. Jakobtorweihen, S., Verbeek, M.G., Lowe, C.P., Keil, F.J., Smit, B.: Physical Review Letters, 2005, 95[4], 044501